DETERMINATION OF APPROXIMATE VALUES FOR BUNDLE ADJUSTMENT *)
Kurt Novak
Vienna Technical University
Vienna, Austria
ABSTRACT
Bundle adjustment algorithms need both approximate values and control
points to calculate the orientation of photographs. This paper
presents methods how to derive the parameters of the interior and
exterior orientations from image coordinates only. Geometrical
relations at the object are used instead of control points.
Goedetical determination of control points is not necessary. An
example shows the practical use of these approaches and compares the
results with bundle adjustment.
1 INTRODUCTION
In terrestrial photogrammetry, non-metric cameras are frequently used
as they are easier to handle and not as heavy as metric cameras.
Generally the position of the projection center and the tilt angles of
the image plane as well as the principal distance and principal point
of a photograph are calculated by bundle adjustment. Control points
measured by goedetical means and approximate values of all parameters
are necessary. These approximate values are either roughly estimated
or geodetically determined.
The approaches described in this paper derive the orientation
parameters directly from the image coordinates without exterior
information but the object form. For calculating the exterior
orientation of two photographs, a plane object is necessary /2//7/.
If three photographs are available, the principal distance can be
found additionally. To get the complete interior orientation from one
or more images, orthogonal directions at the object are used /1//6/.
The lens distortion may be neglected as a distortion polynom can be
defined in a following bundle adjustment.
*) This paper is part of a thesis to gain the title Doctor of
technical sciences at the Technical University of Vienna /5/.
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TC ES